Electric radiant heating panel



H. H- WlLLlAMS ELECTRIC RADIANT HEATING PANEL Filed May 11, 1964 UnitedStates Patent 3,277,273 ELECTRIC RADIANT HEATING PANEL Harry H.Williams, 1300 Gilman St., Muncie, Ind. Filed May 11, 1964, Ser. No.366,508' 2 Claims. (Cl. 219-345) This invention relates to electricheating apparatus for buildings, and more particularly to a panel whichcan be secured to the building-frame and which will contain anelectrical resistance heating element.

It has heretofore been proposed to incorporate electrical resistanceheating elements in panels adapted to provide the wall or ceilingsurfaces in a building. In one such panel, shown in the Deacon PatentNo. 3,095,491, the rear face of the panel is provided with a serpentinegroove in which an insulated resistance wire is laid and covered with aheat-conductive cement or plaster, the rear face of the panel being thencovered with a sheet of paper or metal foil. It is an object of thisinvention to improve panels of that general type, particularly withregard to their ability to radiate the heat generated in the resistancewire.

A preferred form of heating panel embodying my invention comprises asheet of plaster board or gypsum board of conventional type provided inits rear face with a serpentine groove, the ends of which extend intoone edge of the sheet. In its cross-sectional shape, such groove iscoordinated with the cross-sectional shape of the insulation with whichthe resistance wire is covered. If that insulation is circular incross-section, the groove has a semi-circular bottom and a widthdesirably slightly less than the diameter of the insulation, so that theinsulated wire, when forced into the groove, will have goodheattransmitting contact with the side walls and bottom of the groove.After the wire has been seated in the groove, the groove is filled witha heat-transmitting cement to a level flush with the rear face of thepanel, and such rear face is then covered with one or more sheets ofmaterial such as paper or metal foil secured to the panel face. Metalfoil is preferred for this purpose because of its heatreflectiveproperties. The ends of the resistance wire are brought out of the panelthrough the ends of the wirereceiving groove to extend from the edge ofthe panel for connection to appropriate leads.

Instead of employing an insulated resistance wire in which theinsulation is circular in cross-section, I may employ a wire havinginsulation which is square or rectangular in cross-section. With suchawire, the crosssectional shape of the panel groove would conform tothat of the insulation, so that when the resistance wire is forced intothe groove its exposed face will be substantially flush with the rearface of the panel, thus eliminating the necessity for the application ofheat-conductive cement to remove air gaps which would retardtransmission to the panel of heat generated in the wire.

Further objects and features of the invention will become apparent fromthe following more detailed description and from the accompanyingdrawing in which:

FIG. 1 is a perspective view of a ceiling construction showing heatingpanels secured to the lower faces of ceiling joists;

FIG. 2 is a plan view of the rear face of a heating panel;

FIG. 3 is a fragmental vertical section on an enlarged scale taken onthe line 3-3 of FIG. 2; and

FIG. 4 is a vertical section similar to FIG. 3 but illustrating amodified construction.

In the construction shown in FIG. 1, a plurality of heating panels aresecured to the lower faces of a series of ceiling joists 11. As morefully shown in FIGS. 2 and 3, each of the panels 10 comprises arectangular sheet 12 of gypsum board, plaster board, or likefire-resistant material the upper surface of which is provided withPatented Oct. 4,1966

i a continuous serpentine groove 13 for the reception of an insulatedresistance wire. The end portions of the groove 13 are located adjacenteach other and extend into a side face of the sheet 12 whereby the endsof the resistance wire in the groove can be brought out through the sideface of the panel, as indicated at 14, for connection to appropriateleads. The resistance wire, which is designated by the reference numeral15 in FIG. 3, has a sheath or covering 16 of flexible insulatingmaterial. Preferably, although the covering 16 is electricallyinsulating, it is relatively heat-conductive in order to promotetransfer to the sheet 12 of the heat generated by passage of currentthrough the wire. Such coverings are known and form no part of thepresent invention.

In accordance with one feature of my invention, the groove 13 has awidth somewhat less than the diameter of the insulating covering 16 onthe wire 15 with the result that the covered wire has to be forced intothe groove with some accompanying elastic distortion or compression ofthe covering 16. Such compression or distortion of the covering 16increases both the area and firmness of contact between it and the sidewalls of the groove, thus promoting the transfer of heat from the wire15 through the covering to the sheet 12. Further to promote such heattransfer, at least the bottom of the groove conforms to thecross-sectional shape of the covering 16. That is, if the covering 16 iscircular in cross-section, the bottom of the groove is semi-circular insection. The groove may be either formed in the sheet 12 in the moldingthereof or cut in the sheet after the sheet is otherwise finished.

In the arrangement shown in FIG. 3, after the insulated wire is forcedto the bottom of the groove 13, the groove is filled to a level flushwith the upper face of the sheet 12 with a settable cement or plaster17. Such plaster eliminates all air gaps between the surface of the wirecovering 16 and the walls of the groove 13, and hence promotes heattransfer to the sheet 12. To that end, the cement 17, is preferably of atype which possesses relatively good heat-transmitting properties.

After the upper portion of the groove 14 has been filled with cement,the upper face of the sheet 12 is covered with a sheet 18 of paper ormetal foil adhesively secured to the sheet. Metal foil is preferred as amaterial for the sheet 18 because of its heat-reflective properties.

Prepared as just described, the panel is in condition for application tothe frame-work of a building. As shown in FIG. 1, the panel is appliedto ceiling joists 11; but, if desired, it could be disposed in avertical plane and applied to studding. After application to thebuilding frame-work, the projecting wire-ends 14 are bent, upwardly inthe construction shown in FIG. 1, out of the plane of the panel forconnection to appropriate leads, not shown. The panels may be secured tothe building framework by nails driven through them at points spacedfrom the wire-receiving grooves 13.

Instead of employing a covering 16 of the conventional circularcross-section for the wire 15, I may provide such wire with a covering20 (FIG. 4) which is square or rectangular in cross-section. When such awire-covering is employed, the groove 21 in the sheet 12 is shaped incrosssection to conform to that of the covering; but again, the width ofthe groove is desirably slightly less than the width of the covering sothat the latter will undergo some compression as it is forced into thegroove. If the depth of the groove 21 is equal to the vertical dimensionof the covering 20, the upper surface of the covering will lie flushwith the upper face of the sheet 12 and there would be no necessity forthe cement 17 shown in FIG. 3.

A panel constructed in accordance with my invention is very effective inits utilization of the heat generated in the resistance wire. This isdue in large part to the fact that the insulating covering on the wireis compressed when in position and is held in firm and direct contactwith the walls of the groove for at least the lower half of itscircumference. In the arrangement shown in FIG. 4, the covering is incontact with the groove walls for three-fourths of its circumference;and, since the covering completely fills the groove, the application ofplaster or cement to eliminate air gaps is not necessary.

I claim:

1. A radiant heating panel for application to building frame-work,comprising a sheet of fire resistant material having substantially planefront and rear faces and provided in its rear face with a serpentinegroove having opposed side walls, and an electrical resistance wireprovided with a flexible, compressible electrically-resistive coveringseated in said groove, the width of the groove being less than the Widthof the covering, whereby the covering will be compressed between theopposed side walls of the groove and in intimate, heat-transferringcontact with the side walls and bottom of the groove, said coveringsubstantially filling the groove and having an outer face substantiallycoplanar with the rear face of said sheet.

2. A radiant heating panel for application to building frame-work,comprising a sheet of fire-resistant material provided in its rear facewith a serpentine groove, an electrical resistance wire provided with aflexible electricallyresistive covering laid in said groove, saidcovering and groove having substantially identical rectangularcrosssections whereby the covering is in intimate, heat-transmitingcontact with the sides and bottom of the groove, and a sheet ofheat-reflective material covering and adhesively secured to the rearface of said first named sheet and in contact with the otherwise exposedface of said covering.

References Cited by the Examiner ANTHONY BARTIS, Acting PrimaryExaminer.

RICHARD M. WOOD, Examiner.

C. L. ALBRITTON, Assistant Examiner.

1. A RADIANT HEATING PANEL FOR APPLICATION TO BUILDING FRAME-WORK,COMPRISING A SHEET OF FIRE RESISTANT MATERIAL HAVING SUBSTANTIALLY PLANEFRONT AND REAR FACES AND PROVIDED IN ITS REAR FACE WITH A SERPENTINEGROOVE HAVING OPPOSED SIDE WALLS, AND AN ELECTRICAL RESISTANCE WIREPROVIDED WITH A FLEXIBLE, COMPRESSIBLE ELECTRICALLY-RESISTIVE COVERINGSEATED IN SAID GROOVE, THE WIDTH OF THE GROOVE BEING LESS THAN THE WIDTHOF THE COVERING, WHEREBY THE COVERING WILL BE COMPRESSED BETWEEN THEOPPOSED SIDE WALLS OF THE GROOVE AND IN INTIMATE, HEAT-TRANSFERRINGCONTACT WITH THE SIDE WALLS AND BOTTOM OF THE GROOVE, SAID COVERINGSUBSTANTIALLY FILLING THE GROOVE AND HAVING AN OUTER FACE SUBSTANTIALLYCOPLANAR WITH THE REAR FACE OF SAID SHEET.